GLEIF CESR Proof Signatures are an extension to the Composable Event Streaming Representation [CESR] that provide transposable cryptographic signature attachments on self-addressing data (SAD) [SAID]. Any SAD, such as an Authentic Chained Data Container (ACDC) Verifiable Credential [ACDC] for example, may be signed with a CESR Proof Signature and streamed along with any other CESR content. In addition, a signed SAD can be embedded inside another SAD and the CESR proof signature attachment can be transposed across envelope boundaries and streamed without losing any cryptographic integrity.